If a multi-threaded program calls fork(), TSan ignores all memory accesses
in the child to prevent deadlocks in TSan runtime. This is OK, as child is
probably going to call exec() as soon as possible. However, a rare deadlocks
could be caused by ThreadIgnoreBegin() function itself.
ThreadIgnoreBegin() remembers the current stack trace and puts it into the
StackDepot to report a warning later if a thread exited with ignores enabled.
Using StackDepotPut in a child process is dangerous: it locks a mutex on
a slow path, which could be already locked in a parent process.
The fix is simple: just don't put current stack traces to StackDepot in
ThreadIgnoreBegin() and ThreadIgnoreSyncBegin() functions if we're
running after a multithreaded fork. We will not report any
"thread exited with ignores enabled" errors in this case anyway.
Submitting this without a testcase, as I believe the standalone reproducer
is pretty hard to construct.
llvm-svn: 205534
Add the test infrastructure for testing lib/profile and a single test.
This initial commit only enables the tests on Darwin, but they'll be
enabled on Linux soon after.
<rdar://problem/16458307>
llvm-svn: 205256
Soon there will be an option to build compiler-rt parts as shared libraries
on Linux. Extracted from http://llvm-reviews.chandlerc.com/D3042
by Yuri Gribov.
llvm-svn: 205183
These interceptors require deep unpoisoning of return values.
While at it, we do the same for all other pw/gr interceptors to
reduce dependency on libc implementation details.
llvm-svn: 205004
It's hard to write a reliable test for this code because they
work with unpredictable memory locations. But this change should
fix current failures in getpwent() tests on the sanitizer bots.
llvm-svn: 205002
Expose the number of DFSan labels allocated by adding function dfsan_get_label_count().
Patch by Sam Kerner!
Differential Revision: http://llvm-reviews.chandlerc.com/D3109
llvm-svn: 204854
The interceptors had code that after macro expansion ended up looking like
extern "C" void memalign()
__attribute__((weak, alias("__interceptor_memalign")));
extern "C" void __interceptor_memalign() {}
extern "C" void __interceptor___libc_memalign()
__attribute__((alias("memalign")));
That is,
* __interceptor_memalign is a function
* memalign is a weak alias to __interceptor_memalign
* __interceptor___libc_memalign is an alias to memalign
Both gcc and clang produce assembly that look like
__interceptor_memalign:
...
.weak memalign
memalign = __interceptor_memalign
.globl __interceptor___libc_memalign
__interceptor___libc_memalign = memalign
What it means in the end is that we have 3 symbols pointing to the
same position in the file, one of which is weak:
8: 0000000000000000 1 FUNC GLOBAL DEFAULT 1
__interceptor_memalign
9: 0000000000000000 1 FUNC WEAK DEFAULT 1 memalign
10: 0000000000000000 1 FUNC GLOBAL DEFAULT 1
__interceptor___libc_memalign
In particular, note that __interceptor___libc_memalign will always
point to __interceptor_memalign, even if we do link in a strong symbol
for memalign. In fact, the above code produces exactly the same binary
as
extern "C" void memalign()
__attribute__((weak, alias("__interceptor_memalign")));
extern "C" void __interceptor_memalign() {}
extern "C" void __interceptor___libc_memalign()
__attribute__((alias("__interceptor_memalign")));
If nothing else, this patch makes it more obvious what is going on.
llvm-svn: 204823
Change the name of the default profile dumped by compiler-rt to
default.profraw. This distinguishes it more clearly from the
(incompatible) format output by llvm-profdata that is read by clang
-fprofile-instr-use.
llvm-svn: 204676
Make vector clock operations O(1) for several important classes of use cases.
See comments for details.
Below are stats from a large server app, 77% of all clock operations are handled as O(1).
Clock acquire : 25983645
empty clock : 6288080
fast from release-store : 14917504
contains my tid : 4515743
repeated (fast) : 2141428
full (slow) : 2636633
acquired something : 1426863
Clock release : 2544216
resize : 6241
fast1 : 197693
fast2 : 1016293
fast3 : 2007
full (slow) : 1797488
was acquired : 709227
clear tail : 1
last overflow : 0
Clock release store : 3446946
resize : 200516
fast : 469265
slow : 2977681
clear tail : 0
Clock acquire-release : 820028
llvm-svn: 204656
Since the profile can come from 32-bit machines, the reader needs to
check the pointer size. Change the magic number to facilitate this.
<rdar://problem/16400648>
llvm-svn: 204556
This is a bit of a stab in the dark as I'm not sure I've got these
source files compiling correctly locally. (and the warning only
reproduces on a 32bit build anyway)
llvm-svn: 204521
Apparently, MSVC has stdint.h now? Let's see if the buildbots complain.
I'm not convinced that the build system is even set up for MSVC to build
this file, but...
llvm-svn: 204515
Write __llvm_profile_write_buffer(), which uses the same logic as
__llvm_profile_write_file(), but writes directly to a provided `char*`
buffer instead.
<rdar://problem/15943240>
llvm-svn: 204499
It was misguided to plan to rely on __llvm_profile_write_buffer() in
__llvm_profile_write_file(). It's less complex to duplicate the writing
logic than to mmap the file.
Since it's here to stay, move `FILE*`-based writing logic into
InstrProfilingFile.c.
<rdar://problem/15943240>
llvm-svn: 204498
Move functions around to prepare for some other changes.
- Merge InstrProfilingExtras.h with InstrProfiling.h. There's no
benefit to having these split.
- Rename InstrProfilingExtras.c to InstrProfilingFile.c.
- Split actual buffer writing code out of InstrProfiling.c into
InstrProfilingBuffer.c.
- Drive-by corrections of a couple of header comments.
<rdar://problem/15943240>
llvm-svn: 204497
Using __msan_unpoison() on null-terminated strings is awkward because
strlen() can't be called on a poisoned string. This case warrants a special
interface function.
llvm-svn: 204448
Add logic to do a printf-style substitution of %p for the process pid in
the filename.
It's getting increasingly awkward to work on lib/profile without test
infrastructure. This needs to be fixed!
<rdar://problem/16383358>
llvm-svn: 204414
These functions are in the profile runtime. PGO comes later.
Unfortunately, there's only room for 16 characters in a Darwin section,
so use __llvm_prf_ instead of __llvm_profile_ for section names.
<rdar://problem/15943240>
llvm-svn: 204391
__llvm_pgo_write_default_file() was a bad name, since it checked the
environment (it wasn't just a default file).
- Change __llvm_pgo_write_file() to __llvm_pgo_write_file_with_name()
and make it static.
- Rename __llvm_pgo_write_default_file() to __llvm_pgo_write_file().
- Add __llvm_pgo_set_filename(), which sets the filename for
subsequent calls to __llvm_pgo_write_file().
<rdar://problem/15943240>
llvm-svn: 204381
Instead of relying on explicit static initialization from translation
units, create a new file, InstrProfilingRuntime.cc, with an
__llvm_pgo_runtime variable. After this commit (and its pair in clang),
the driver will create a use of this variable. Unless the user defines
their own version, the new object file will get pulled in, including
that C++ static initialization that calls
__llvm_pgo_register_write_atexit.
The result is that, at least on Darwin, static initialization typically
consists of a single function call, which registers a writeout functino
atexit. Furthermore, users can skip even this behaviour by defining
their own __llvm_pgo_runtime.
<rdar://problem/15943240>
llvm-svn: 204380
Extend ParseFlag to accept the |description| parameter, add dummy values for all existing flags.
As the flags are parsed their descriptions are stored in a global linked list.
The tool can later call __sanitizer::PrintFlagDescriptions() to dump all the flag names and their descriptions.
Add the 'help' flag and make ASan, TSan and MSan print the flags if 'help' is set to 1.
llvm-svn: 204339
Hans Wennborg